/*
 * Copyright (c) 2016, 2016, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package com.oracle.truffle.regex.tregex.util;

import java.io.BufferedWriter;
import java.io.IOException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class DotExport {

    public static void printConnection(BufferedWriter writer, String from, String to, String label) throws IOException {
        writer.write(String.format("    \"%s\" -> \"%s\" [ label = \"%s\" ];", escape(from), escape(to), escape(label)));
        writer.newLine();
    }

    private static final Pattern specialChars = Pattern.compile("[\"\\\\]");

    public static String escape(String str) {
        StringBuffer escapedString = new StringBuffer();
        Matcher m = specialChars.matcher(str);
        while (m.find()) {
            String replacement;
            switch (str.charAt(m.start())) {
                case '"':
                    replacement = "\\\\\"";
                    break;
                case '\\':
                    replacement = "\\\\\\\\";
                    break;
                default:
                    throw new IllegalStateException();
            }
            m.appendReplacement(escapedString, replacement);
        }
        m.appendTail(escapedString);
        return escapedString.toString();
    }
}
